Augustus schultz



.without the addition of an acid.

AUGUSTUS SCHULTZ, OF NEIV YORK, N. Y.

TAWlNG HIDES AND SKiNS.

SPECIFICATION forming part oi Letters Patent No. 291,784, dated January 8, 1884.

Application filed May 31, 1883. (No speclmens.)

To all whom it may concern Be it known that I, AUGUSTUS ScnUL'rz, a citizen of the United States, residing at New York, in the county and State of New York, have invented a new Improved Process of Tawing Hides and Skins, of which the following is a specification.

This invention relates to a new process for tawing hides or skins, said process consisting in subjecting said hides or skins to the action of compounds of metallic saltssuch as bichromate of potashaud then treating the same with hyposulphite of soda, by which term is understood. that salt which is more recently sometimes called thiosulphate of soda, (Na,S ,O,.)

In carrying out my process, I .unhair the rawhides and prepare them in the same manner in which they are made ready for tanning. If the hides have not been pickled, I subject them to the action of a solution of bichromate of potash in the presence of an acid-such as hydrochloric acidor, if the hides have been pickled, they may be treated in a solution of bichromate of potash in water In this solu tion the hides are left for a shorter or longer time, according to their thickness and to the strength of the solution employed. A skiver or the face of a sheep-skin can be done in a strong solution, as above described, in about fifteen minutes, 'while a full skin roan would require in the same solution about one hour. I call the solution weakif it contains five per cent. or less of the weight of skins of bichromate of potash, and I call the solution strong it it contains more than five per cent. of bichromate of potash. It is not material, however, how strong the solution is. The skins are completed ifsinall pieces cut from the thickest parts of said skin show that the solution has entirely penetrated. The skins are then ready to be taken out, and after the adhering liquor has run off the skins are introduced into the second solution, which consists of hyposulphite of soda dissolved in water, and adding an acid, such as hydrochloric acid. The solution may be strong or weak of hyposulphite, and the quantity of acid used at first may be less than requisite to split up the entire quantity of hyposulindicated by the color of the skins.

phite, and more acid may be added if the skins show that more is required, which is hen they are done, they show a whitish, blueish, or greenish color, according to the time they are kept in the hyposulphite solution. A skiver which first has been exposed to the action of the bichromate for fifteen minutes will be ready by remaining in the hyposulphite solution about twenty minutes. For thicker skins a proportionately longer time is required. For some skins-such as calf or steers skinsit is desirable that the same, after having been withdrawn from the second or hydrosulphite solution, shall be returned to the bichromate solution, which imparts to them a brownish color and leaves them in a favorable condition to be colored black. The coloring can be done after the skins leave the hyposulphite solution, and after they have been exposed for the second time to the bichromate solution. The leather coming from the hyposulphite solution is especially adapted for'light or dark colors, and by proper dyeing methods better and brighter colors can be produced than on leather done by tanning. Aft-er the leather is treated in the manner above indicated, it may be colored, soaped, and greased in the usual way. Leather can also be made by reversing the operation and first soaking the hides in a solution of hyposulphite of soda and then exposing them to. the action of the bichromate solution. By using the solutions indicated at a heat of about 80 Fahrenheit, the process will be done in a shorter time than if the solutions are used cold. By my process the gelatine contained infthe hides is rendered insoluble by means not injurious to the leather. If leather made by tannin is put in a strong soda solution, the tannin is extracted and a dark-brown liquor is formed. If leather made by my process is put in a strong soda solution, the liquor obtained shows only a little milky color.

Leather made by my process is very strong, soft, elastic, and my process is applicable to hides or skins of every description.

\Vhat I claim as new, and desire to secure by Letters Patent, is

The within-described process for tawing hides and skins, said process consisting in sub- IOO j ecting the hides or skins to the action of com- In testimony whereof Ihave hereunto set my pounds of metallic salts such as a solution of hand and seal in the presence of two subscrib-' I bichromate of potash-and then treating the ing witnesses.

same with a compound containing hyposul- 5 phurous acid, (or as it is otherwise called thio- AUGUSTUS SCHUL 1 sulphuric acid,) such as a solution of hypo- \Vitnesses: snlphite of soda or of potash in the presence of hydrochloric acid.

W. HAUFF, XVILLIAM MILLER. 

